Looper-actuating mechanism for sewing machines



R. BECKER April 6, 1948.,

LOOPER-ACTUATING MECHANISM FOR SEWING MAQHINES 4 Sheets-Sheet 1 Filed Nov. 28, 1945 k an mu yfwdolpk @ecer April e, 1948.

R. BECKER LOOPER-ACTUATING MECHANISM FOR SEWING MACHINES Filed Nov. 28, 1945 4 Sheets-Sheet 2 Qwdolplzz Z8 cer April 6, 1948. I R. BECKER 2,4 39,332

' LOOPER-ACTUATING MECHANISM FOR SEWING MACHINES Filed Nov. 28, 1945 4 sneets sheet 3 April 6, 1948. R. BECKER 2, 9,

LOOPER-ACTUATING MECHANISM FOR SEWING MACHINES 7 Filed Nov. 28, 1945 4 Sheets-Sheet 4 Patented Apr. 6, 1948 LoorEn-Ac'r ATING MECHANISM on SEWING MAoniuEs Rudolph Becker, North Plainfield, N. J assignor to The Singer Manufacturing Company, Elizabeth, N. J a corporation of New Jersey Application November 28, 1945, Serial No. 631,303

This invention relates to chain-stitch sewing machines of the type employing a thread-carrying needle and a cooperating oscillatory threadcarrying looper.

The invention has as a primary object to provide improved actuating means for the looper, whereby the looper will have a path of movement which will greatly facilitate the taking, holding and shedding of the needle-thread loop.

Another object of the invention is to provide an improved variable speed looper-actuating means which will move the looper at a decelerating speed during the latter portion of its loopseizlng stroke and at an accelerating speed during the major portion of its loop-shedding stroke.

A further object is to provide an improved variable speed looper-actuating mechanism and so to coordinate the movements of the looper with the movements of the needle'that the stroke of the looper may be greatly reduced, as compared with prior constructions.

Still another object is to provide an improved looper-actuating mechanism which is particularly well adapted for wide gauge and multiple needle sewing machines.

With the above and other objects in view, as will hereinafter appear, the invention comprises the devices, combinations and arrangements of parts hereinafter set forth and illustrated in the accompanying drawings of a preferred embodiment of the invention, from which the several features of the invention and the advantages attained thereby will be readily understood by those skilled in the art.

In the drawings,

Fig. 1 is a front side elevation, partly in section, of a chain-stitch sewing machine embodying the present invention, with certain parts omitted for the sake of clearness.

Fig. 2 is an enlarged plan view of a portion of the machine base and the parts carried thereby, with certain cover plates and portions of the workfeeding mechanism omitted.

Fig. 3 is an enlarged transverse sectional view taken substantially on the line 3-3 of Fig. 2, and showing additionally certain elements of the work-feeding mechanism which are omitted from Fig. 2.

Fig. 4 is an enlarged tranverse sectional view taken on the line 4-4 of Fig. 2.

Figs. 5, 6, 7 and 8 are a series of views of the needle and looper of the machine at different successive stages of a stitch-forming cycle.

Fig. 9 is an enlarged diagrammatic view illustrating the path of movement of'the looper in 16 Claims. (01. 112-199) conjunction with various positions of the needle; the looper being indicated in the positions to which it is moved by successive angular movements of thirty degrees each of the main shaft of the machine.

Fig. '10 is a diagrammatic view illustrating the action of a loop-spreader, later to be described, in conjunctionwlth the looper and the needle? Fig. 11 is an enlarged sectional view taken substantially on the line I l--l l of Fig. 2.

Referring more specifically to the drawings, the invention is disclosed as embodied in a sewing machine having a frame comprising a pan-like bed or base l5, a standard it and an overhanging bracket-arm ll terminating in a bracket-arm head "It. :Jour'naled in bearings l9, lengthwise of the bracket-arm, is a main or arm shaft 20 carrying, at its rear end, a combined belt and hand wheel 2] through which the shaft 25 is driven from any suitable source of power.

"Mounted in the head l8, for endwise reciprocation, are two'needle-bars 22, each having so cured to its lower end, ablock 23.

horizontally disposed rods 24 upon which may be adjustab-ly secured a plurality of need1e carrying blocks 25 each generally similar to the blocks 23. Each of the blocks 25 is adapted to carry a needle N, only three of which are shown. Any suitable number of needle-carrying blocks 25 may be mounted upon the rods 24 and, by adjusting them along the rods and securing them thereto, any desired'spacing of the needles and consequently any desired spacing of the seams formed thereby may be obtained. Cooperating with each of the needles in the formation of stitches, is a thread-carrying chainstitch looper L, also of which only three are shown. Each of the loo-pers L is secured in an oscillatory looper-carrier 26 in proper position to cooperate with its complemental needle. The looper-carrier, and the loopers carried thereby, are giverios'cillatory and orbital movements from a rotary feed and looper actuating sh'aft2'l, jour naled in bearings 28 in the base, through mech anism hereinafter to be described.

The shaft 21 is rotated from the main shaft 20 through the medium of'a one-to-one pulley and clip-belt drive, located in a vertically disposed cavity It in the standard 16, and comprising a slotted pulley 25 on the shaft 25), a similar pulley 21 on the shaft 21 and a clip-belt 29 connecting these pulleys. The needle-bars 22, and the needles carried thereby, are given endwise reciprocations from Secured in and extending through the blocks 23 are two is below the upper face of the throat-plate, the

work is held on the throat-plate by two presserfeet 31 (of which one is shown) each pivotally mounted upon a shank 3W, secured ,to thelower end of a spring-depressed presser-bar (not shown) mounted in the head I8.

The feeding mechanism may be of suitable or preferred construction, such, for example, as that disclosed in my United StatesPatent No, 2,409,242, October 15, 1946.

. The looper-carrier 26 is formed in its ends with transverse grooves 3.2 and 33 which receive tongues 34 and 35, respectively, formed on the adjacent ends of aligned looper-driving shafts 39 and 31. The looper-carrier is secured to the shafts 36 and 31 by clamp screws 39, carrying washers 39, and set screws 49. Each looper is formed with a depending cylindrical shank s, fitted into a boreb in the looper-carrier 26 and held therein by a set screw 4|. The lower end portion of each looper shank is formed with a transverse thread aperture 42 which moves relative to and cooperates with fixed thread-guides 43 and 44, to pull looper thread t from the supply and to serve as a take-up for the looper thread. The thread-guides 43 and Mare carried, respectively, by angle-bars 45 and 46 secured to the base it of the machine.

The looper-carrier 29 and the shafts 38 and 31 form, in effect, a single composite looper-carrying and -aot uating shaft, the portion 26 being made removable from the portions 36 and 31 so that it may be removed and interchanged with other similar portions each having a different arrangement of looper-receiving bores b, whenever it is desired to employ a different number or spacing of needles and loopers.

To the end that the composite looper shaft 36, 29, 37, be operated smoothly and without "any binding or cramping action, means is provided for actuating the shaft synchronously from each end thereof, as hereinafter will be described.

The looper shaft sections 35 and 31 are journaled, respectively, in eccentric bores 41 and 18 formed in bushings 49 and 59 which carry eccentric gears 9i and 52. The bushings G9 and 59 are journaled in bearing sleeves 53 and 54 secured in the base of the machine. The bushings 49 and 59 are held against endwise movement in one direction by hubs on the gears 5i and 52 abutting the outer ends of the bearing sleeves and in the other direction by disks 5? and 54* secured to the bushings 49 and 50 and bearing against annular shoulders 49* and 59* provided by the sleeves 53 and 59, respectively. Collars 39 and 31*, secured upon the shaft sections 36 and 31 and abutting the disks 53 and 5 hold the composite looper shaft against endwise movement.

Secured eccentrically upon the shaft 2! are two looper-driving gears55 and'iifi complemental to and driving, respectively, the gears 5! and 52 on the composite looper-actuating shaft. Thus rotation of the shaft 21 effects, through the eccentric gears 555! and 5552, rotation, at a varying rate, of the bushings 49 and 93 in their hearing sleeves 53, 5'3, thereby moving the composite looper-actuating shaft laterally of its axis in an orbit or around a field which is designated as y in Figs. 4, 5, 6', 'l and 8.

During the variable speed rotation of the looper-shaft about the field y the looper shaft is also oscillated on its own axis. This oscillation is effected by an eccentric or crank 51 formed on the shaft 21 and embraced by a split block 53, having in its lower portion a cylindrical bore 59. Slidingly fitted within the bore 59 is a pin 69 formed integral with a split head 94 secured by screws 52 and 63 upon the portion 3? of the looper-actuating shaft.

. Figs. 5, 6, 7 and 8 show one of the needles, and its complemental looper, and the supporting and actuating mechanism for the looper in different successive positions which they assume during the formation of a stitch. These positions correspond, respectively, to the positions of the looper numbered 2, 5, 9 and i i in Fig. 9 in which the entire cycle of the looper and the path of travel of the looper-eye together with the corresponding positions of the point of the needle are illustrated on an enlarged scale.

Assume now that in Fig. 9 the needle is carrying an upper thread n and, the looper is carrying a lower thread if, as in Figs. 5, 6, 7- and 8, with thelower thread passing through a first eye 6 in the heel of the looper, then extending alonga groove in the blade thereof and finally back through an eye 6' adjacent the point of the looper, as shown in Fig. 10. Assume further that the needle has penetrated the work andhas car ried its thread with it to its lowermost position, indicated as '9 (zerolin Fig. 9. The looper, is substantially in its most retracted position, also as indicated by the position 9 (zero) of t he loop.er eye e. Successive turning movements of the main shaft 29 of thirty degrees each move the looper-eye and the needle successively to the positions designated as], 2, 3, l, 5, 6, L8, 9, is,

H and finally back to zero. During the first sixty degrees rotation of the main shaft, the needleis retracted from zero position to the position designated as 2, during which it casts out a loop Z of the needle thread. The looper advances from zero position to the position numbered 2 in ig. 9 and, as shown in Fig. 5, enters the needlethread loop 1.. The nextninety degrees rotation of the main shaft retracts the needle andadvances the looper tothe positions numbered 9 in Fig. 9, and shown in Fig. 6, thereby carrying its thread through the .needleethread loop and retaining thereon the needle-thread loop which slides along the looper-blade and into the throat thereof as shown in Fig. 6; g

In advancing from zero position to position Number 4, the looper moves forwardly and downwardly, at a rapid rate, in a substantially straight path, thus greatly facilitating thetaking of the needle-thread loop. The looper moves slowly between positions .4 and], thereby giving the needle time to retract from its Number 5 position to its uppermost position (Number 5), to reverse its direction of movement and to advance to position Number "5.

The looper, is then retracted rapidly from position 1 to position 9,;which is shown in Fig. 7. During this movement thelooper rollsupwardly and backwardly, thereby facilitating its partial withdrawal from the needle-thread loopwhich is then held around the blade of. the looper. Also during this movement, the looper thread t is engaged by a laterally movable spreader finger 65, later to be described, which moves a portion of thelooper thread laterally, as shown in Fig. 10, thereby forming a triangle between the looper thread and the blade of the looper into which triangle the needle descends and carries its thread. 7

A further sixty degree rotation of the main shaft retracts the looper from the position 9, shown in Fig.7, to the position ll, shown in Fig. '8, thus causing the looper to shed the previously engaged needle-thread loop which thereupon is drawn up and tightened by the needle-thread take-up, thereby completing the concatenation of the two threads in a two-thread chain-stitch. After the needle has entered the looper-loop, retracting of the looper effects a relative movement between the thread=eye 42, in the shank s of the looper, and the fixed thread guides 43 and M, thereby tightening the stitch and drawing looper thread from the supply.

Due to the fact that the looper is moved upwardly toward the throat-plate during its retractive loop-shedding movement, the point of the looper is closely adjacent the work when the needle-loop is shed from the looper, thereby re quiring very little take-up action to tighten and set the stitch. H

In its final descent, thepoint of the needle passes between spaced walls of a sheet metal needle guide 66 carried by the shank of the looper, which guide insures the proper positioning of the needle for the taking of the next needle-loop by the loop-taker.

The final thirty degrees of rotation of the main shaft moves the needle and looper from their number ll position back to zero position preparatory to the beginning of a new cycle of operation.

The spreader 65, liereinbefore referred to, of which there are as many as the number of loopers employed, is secured to a horizontally disposed member 61 slidingly mounted in a channel '63 in the under sideof the throat-plate 28. At one end the member .61 is connected to a slide-bar G9 slidingly mounted within a slideway 10 formed in the under side of a block H secured to the base of the-machine. The slide-bar carries a roller-stud 12 which tracks a cam-groove 13 formed in a cam-disk 14 secured to the face of the gear 5], as by screws 15.

Having thus set forth the nature of the invention, what I claim herein is:

' 1. In a two-thread chain-stitch sewing machine having a reciprocatory eye-pointed needle, a thread-carrying looper formed with a blade having a loop-seizing beak, means to move said looper in an orbit about a field parallel to the needle, and means to oscillate said looper in the plane of and in time with itsorbital movement so that the looper-blade moves in a downwardly inclined substantially straight path when advancing to seize a needle-loop and has anupwardly inclined movement in a curved path above the first named path when shedding the needle loo 2 In atwo-thread sewing machine, the combination with a reciprocatory eye-pointed needle, of a thread-carrying looper having a loop-seizing beak, and means including an eccentric gear drive to impart variable speed needle-loop-seizing and -shedding movements to said looper around a field parallel to said needle, while so oscillating the looper in the plane of said field as to give the looper a downwardly inclined substantially 6 straight pathof movement during its lbop-seizing movement and an upwardly inclined curved path of movement during its shedding of the loop.

A looper-mechanism for cooperation with the reciprocatory eye-pointed needle of a twothread chain-stitch sewing machine comprising, a thread-carrying looper, a looper-carrying shaft, and a variable speed driving means to move said shaft bodily sidewise at a "varying rate around a field while oscillating said shaft on its own longitudinal axis.

4. A loop-taking mechanism for two-thread sewing machines comprising, a rotary member, an oscillatory shaft carried by said rotary member eccentrically of and parallel to the axis of rotation of the latter, variable speed means to drive said rotary member, means to oscillate said shaft, and a thread carryi'ng looper mounted on said shaft.

5. A two-thread chain-stitch sewing machine looper mechanism comprising, a frame, a rotary shaft journ'a'led therein, an eccentric carried by said shaft, a strap surrounding said eccentric and affording a tubular bore, a rotory bushing journaled in said frame, a pair of eccentrically journaled gears connecting said shaft with said bushing to rotate the bushing at a variable rate,

a looper-shaft journaled eccentrically in said oscillation of. said looper-shaft by said eccentric, and a thread-carrying looper mounted on said looper-shaft.

6. A mechanical movement for. a sewing machine looper comprising, a driving shaft, an eccentric fixed thereon, a rotatable eccentric bushing, a first eccentric gear secured to said driving shaft, a second eccentric gear, complemental to the first, secured to said bushing, said gears rotating said bushing at a variable rate from a constant rate of rotation of said driving shaft, a second shaftjournaled in said bushing, a sleeve embracing said eccentric and connected to oscillate said second shaft, and a thread-carrying looper carried by said second shaft for variable speed movements about a field.

'7. In a. sewing machine, a shaft, an eccentric gear drive to move said shaft at a varying rate laterally of its axis about a field, means to impart movements of oscillation to said shaft while the latter is being carried around said field, and a thread-carrying loop-taker carried by said. shaft.

-8. In a two-thread chain-stitch sewing machine having a reciprocatory thread-carrying needle, "a thread-carrying looper and means to first move the loop'er in a substantially straight line inclined downwardly to project the looper and its thread through the needle thread loop, then to retract the looper and, simultaneously with the retracting movement, to move the looper upwardly and tip it backwardly until the needle has passed its loop through the looper-loop, and finally to lower the looper to initial position ready for projection into the next needle-loop.

9. In a two-thread chain-stitch sewing machine having a reciprocatory eye-pointed needle, a thread-carrying looperformed with a blade having a loop-seizing beak, means to move said looper in an orbit about a field parallel to the needle, and means to oscillate said looper in the plane of and in time with its orbital movement so that the beak of the looper-blade moves in a substantially plane-convex path in a vertical plane during the seizing and shedding of the loop-seizing and -shedd ing movements to'salda looper around a field parallel to-said needle, while so oscillating the looper in the plane of said field as'to give the looper beak a downwardly inclined substantially straight path of travel during its loop-seizing movement and an upwardly convex path of travel during its loop-shedding move ment.

11."In a sewing machine having a frame in-, cluding a base provided with spaced vertically disposed'walls, a rotary drive shaft ,journaled in bearings in said walls, a rotary bushing journaled in each of said walls and in alignment with each other, a variable speed driving connection from said shaft to each of said bushings, a looper shaft journaled eccentrically in said bushings and rotatable therewith .sidewise about afield; a thread-carrying looper carried bysaid looper shaft, and means actuated by said drive shaft for oscillating said looper shaft during its rotation with said bushings, to cause said looper to be moved in anor bital path at a varying rate.

12. In a sewing machine having a frame in cluding a base provided with spacedyertically disposed walls, a rotary drive shaft journaled in bearings in said walls, a rotary bushing jour naled in each of said walls at one side of and parallel to said shaft and in alignment with each other, an eccentric gear driving connection from said shaft toeach of said bushings,a looper shaft journaled eccentrically in said bushings and rotatable therewith sidewise about a field, a threadcarrying looper carried by said looper shaft, and means actuated by said drive shaftfor oscillating said looper shaft during its rotation with said bushings, tocause said looper to be moved inan cluding abase provided with spaced vertically disposed walls, a rotary drive shaft iournaled in hearings in said walls, a rotary bushing journaled in each of said walls and in alignment with each other, a driving connection from said shaft to each of said bushings, a loo-per shaft journaled eccentricall in said bushings and rotatable therewith sidewise about a field, said looper shaft extending between said spaced walls, a plurality of thread-carrying loopers carried by that portion of the looper shaft between said walls, and means actuated by said drive shaft for oscillating said looper shaft during its rotation'with said bushings, to cause said loopers to be moved in an orbital path.

14. In a sewing machine having a frame in cluding a base provided with spaced vertically disposed walls, a rotary drive shaft J'ournaled in bearings in said walls, a rotary bushing journaled in each of said walls and in alignment with needle in the formation of stitches, and means each wh n d ivin nneetmn' pm said aft:

to-each of said bushings, a looper shaft'jou'rnaled eccentrically vm,said bushingsand rotatable therewith sidewise about a field, saidlooper shaft extending between said spaced'walls-and having,

a portion thereof bodily removable from the nor;- tions journaled in the bushings, a plurality-of thread-carrying loopers carried by the'removable portion of said loopershaft, and means actuated by. said drive shaft for oscillating said looper shaft during its rotation withsaid bushings, to cause said loopers to be moved in an orbital path;

15. In a'two-thread chain-stitch sewing mashaft, means actuated by said drive shaftfor' oscillating said looper shaft during its rotation with said bushings, to cause said looper to be moved in an orbital path, a cam secured to and rotatable with one of said bushings,-a barslidingly mounted in one of said walls and operatively connected with said cam to b reciprocated thereby, and a loop-spreader carried by said bar and movable horizontallybetween the'needle and the looper, to form a bight in the looper thread for entrance by the needle. Q

16. In a two-thread chairi stitch' sewingmachine having a throat-plate provided with a needle-hole, a reciprocatory' thread-carrying needle operating through the needle-hole, a threacl-carrying looper cooperating with 7 said ously with the retracting movement to move the- -looper upwardly and backwardly in a curved path until the needle has passed its loop through the looper-loop, and finally to lower the looperii'to initial position ready for projection into theneict needle=loop, the looper being considerably-closer to'said needle-hole when-shedding theineedlen loop than when entering the same."

RUDOLPH BECKER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name 7 Date 2,224,028 I Becker Dec. 3, 1940 

